A conventional horizontal lathe machine with double spindles and double tooling turrets, such as that disclosed in Taiwanese Utility Model M536108, includes a movable work spindle seat movably mounted on a middle portion of a machine base, and first and second tool holding seats mounted at two opposite sides of the work spindle seat. Spindles of the first and second tool holding seats are disposed parallel to and face toward each other to respectively hold cutting tools for performing a machining process to a workpiece held by the work spindle seat. The work spindle seat has two opposite spindles on which cutting tools are mounted to cut an inner side of the workpiece.
Another conventional three-axis horizontal lathe machine as disclosed in Taiwanese Utility Model M546866 includes a work holding assembly mounted on a middle portion of a machine base, and two machining assemblies mounted at two opposite sides of the work holding assembly, and respectively having cutter changing mechanisms which define movable axes in line with each other.
Although the abovementioned horizontal lathe machines have two tooling turrets, in order for an operator to replace a cutting tool of each of the tooling turrets, each of the tooling turrets is required to be manually and rotatably driven to bring a cutting tool thereof in proximity to the front side of the machine base, i.e., in proximity of the operator for replacement, which can be time-consuming. In addition, during cutting machining operations, since the rotational direction of the turrets is oriented toward the operator, scraps from the workpiece may fly off therefrom, injuring the operator.